Is being on and off birth control healthy?

(This is advice for my friend)
Her boyfriend goes to afganistan for months at a time, shes realigious and agaist abortion 100%, she doesnt want anymore kids, And when he does get to come back after sometimes 4 somtimes 6 even 8 months at a time, they are...

protected with the birthcontrol pill. But she fears it makes her gain weight, and its just a hassle to take when she wont be having sex till he comes back from afganistan. you know? So can she go on for a few months and then randomly back on for a few more months? is it healthy? My friend thinks it will mess up her system inside. But they want to use thebirthcontrol pill, and im not sure if they use condoms or not.

Going on and off birth control can cause it to be un-effective.

If it is sporadic condoms are probably the best birth control
You can go off and on, I mean your body is probably a little confused with the up and down of hormones but I doubt it will cause any harm. Only thing is you usually need to be on the pill for atleast a month before you know it is completly effective...

I dont think its healthy. She needs to find one form of BC and stick to it. It will not prevent pregnancy as effectively as it would if she was using it constantly

birth control pills don't usually work until you have taken them consistently for a month so that would just be useless for her to take them when he comes home. She needs to use condoms, get a birth control shot or patch! Something or she's going to end up pregnant using that method.